<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        div{
            width: 100px;
            height: 100px;
            background-color: red;
            margin: 20px;
            /* 浮动布局 */
            /* float: left; */
            float: right;
        }
        section{
            width: 100px;
            height: 100px;
            border-radius: 50%;
            background-color: pink;
            text-align: center;
            line-height: 100px;
            /* 固定定位 top bottom right left */
            position: fixed;
            bottom: 20px;
            right: 20px;
            
        }
        a{
            /* 取消a标签下划线 */
            text-decoration: none;
            color:blueviolet;
        }
    </style>
</head>
<body>
    <div>1</div>
    <div>2</div>
    <div>3</div>
    <section>
        <a href="#">回到顶部</a>
    </section>
</body>
</html>